1. Field of the Invention
The present invention relates to the field of portable devices such as personal digital assistants or palmtop computer systems. Specifically, the present invention relates to a method and system for preventing unauthorized use of a portable device and for facilitating recovery of the portable device if it is lost or stolen.
2. Related Art
As the components required to build a computer system have reduced in size, new categories of computer systems have emerged. One of the more recent categories of computer systems is the portable or “palmtop” computer system, or personal digital assistant (PDA). A palmtop computer system is a computer that is small enough to be held in the hand of a user and is thus “palm-sized.” As a result, palmtops are readily carried about in a briefcase or purse, and some palmtops are compact enough to fit into a person's pocket. By virtue of their size, palmtop computer systems are also lightweight and so are exceptionally portable and convenient.
On the other hand, because they are relatively small, palmtop computer systems can be easily lost or stolen. Although they are not extremely expensive, palmtops are expensive enough to make them attractive to thieves. To the owner of a palmtop, not only is there a monetary loss if the device is lost or stolen, but the information stored on the palmtop may be very valuable and possibly irreplaceable. Consequently, it is desirable to discourage theft of palmtop computer systems and to encourage their return to their rightful owners when they are lost or stolen.
In addition, it is desirable to prevent use of the palmtop if it is not in the possession of an authorized user. Importantly, this may discourage deliberate acts such as theft if it is known beforehand that the palmtop can only be used by an authorized user. Of further importance, this can prevent information stored on the palmtop from being accessed by someone other than an authorized user.
In the prior art, one method for protecting against unauthorized use of a computer system or against unauthorized access to information stored in a computer system is to use a password. However, passwords are considered by many users to be vexing and inconvenient, passwords can lock out even an authorized user, and experience shows that passwords can be defeated by unauthorized users. In addition, while a password may prevent access to applications and information already existing on the palmtop, it will generally not prevent an unauthorized user from adding new applications and information. Thus, an unauthorized user can simply assume ownership of the palmtop and ignore the password-protected information.